1. Field of the Invention
The present invention relates to a Zigbee device using a neighbor table and a data transmission method thereof, and more particularly, to a Zigbee device which sets up a network via a neighbor table having address information of a device present within electrical power enabling Zigbee communication and transmits data on an optimum path using the neighbor table in the set-up network.
2. Description of the Related Art
In general, Zigbee refers to a low-rate wireless personal area network based on the IEEE802.15.4 standard. In a Zigbee communication system, a frequency is divided into three bands, and spreading and data rates are set differently for each of the frequency bands.
Zigbee is aimed at applications with smaller size, and lower power consumption and costs. Recently, Zigbee has been highlighted as a technology for a local-distance telecommunication market of 10 to 20 cm in a wireless networking of home and office and for ubiquitous computing that has garnered attention.
FIG. 1 is a configuration diagram illustrating a general Zigbee network.
Referring to FIG. 1, the Zigbee network 10 includes a coordinator C and a plurality of devices D1 to D8.
The coordinator C relays information in the Zigbee network 10 and manages a network.
The devices D1 to D8 each may be formed of a router or an end device.
The router enlarges an area of the network 10 and shares a role of the coordinator C.
The end device performs communication in the network 10.
The coordinator C and the devices D1 to D8 of the Zigbee network include a neighbor table, a route discovery table, a routing table and a broadcast table, respectively.
Meanwhile, in the general Zigbee network described above, data is transmitted by a tree method and Ad hoc On-demand Distance Vector (AODV).
By the tree method, a source device transmits data to a child device thereof when a destination device to which the data is to be transmitted is the child device. On the other hand, the source device transmits the data to a parent device thereof when the destination device is not the child device.
By AODV, the source device transmits the data on a shortest path based on the routing table of the devices.
In general, the source device transmits the data in the Zigbee network by a combination of the tree method and the AODV.
That is, to transmit the data by designating the destination device, first, the source device searches the routing table by the AODV. When the destination device is stored in the routing table, the source device transmits the data via a path for the destination device stored in the routing table. On the other hand, when the destination device is not present in the routing table, the source device transmits the data by the tree method.
Then, the source device identifies whether the destination device is the child device thereof by the tree method using an equation defined by a Zigbee alliance. When the destination device is the child device, the source device transmits the data, and when the destination device is not the child device, the source device transmits the data to the parent device.
In the general Zigbee network, the data is easily transmitted by a simple method as described above. However, even in a case where the destination device is located close to the source device, the source device transmits the data through another node when the source device is not connected through a node to the destination node.
For example, referring to FIG. 1, in a case where the arbitrary source device D4 designates the destination device D7 to transmit the data, despite proximity of the source device D4 to the destination device D7, the data is transmitted via a path connecting D4 to D2, and then D2 to D5 and finally D5 to D7.
For another example, in a case where the arbitrary source device D7 designates the destination device D6 to transmit the data, the data is transmitted via a path connecting D7 to D5, and then D2 to C and finally D3 and D6.
As described above, in spite of proximity of the source device to the destination device, the data is transmitted via another node-connected path, thereby unnecessarily delaying transmission time.
This potentially serious problem may cause the Zigbee network system seeking low power consumption to waste unnecessary electrical power and prematurely dissipate electrical power thereof.